JP2703571B2 - New propylene polymerization method - Google Patents

Abstract

A highly efficient process is disclosed for the production of substantially amorphous ethylene-propylene copolymers which are useful as hot melt adhesives, as blending components in roofing materials, and as cable and wire flooding agents. The process involves reacting from 70 to 96.5 wt. % propylene and from 3.5 to 30 wt. % ethylene at a temperature between 55 DEG C (130 DEG F) and 80 DEG C (175 DEG F) and at a reactor pressure sufficient to maintain propylene in the liquid phase, in the presence of from 0.7 to 3.0 mol % hydrogen based on the monomer feed to the process and employing as catalyst a composition comprising: (a) a solid catalyst component obtainable by (i) co-comminuting magnesium halide support base and aluminium trihalide in a molar ratio from 8:0.5 to 8:3 in the absence of added electron donor and (ii) then co-comminuting the product of step (i) in the absence of added electron donor with sufficient titanium tetrahalide to provide a molar ratio of magnesium halide to titanium tetrahalide from 8:0.4 to 8:1 and (b) a co-catalyst component comprising a mixture of from 15 to 100 mol % of trialkyaluminium having from 1 to 9 carbon atoms in each alkyl group and 85 to 0 mole % of an alkylaluminium halide having at least one halide group per molecule and from 1 to 9 carbon atoms in the alkyl group in a sufficient quantity to provide an Al/Ti ratio in the range from 50:1 to 600:1; and recovering a substantially amorphous, random ethylene-propylene copolymer having a tacticity index m/r in the range of from 2.5 to 4 as determined by <1><3>C NMR spectra.

Description

DETAILED DESCRIPTION OF THE INVENTION In the production of propylene homopolymers and copolymers, conventional polymerization techniques using unsupported catalysts, in addition to the desired highly crystalline, highly stereoregular product, The result is that a significant amount of atactic polymer is produced at the same time.
Various methods have been used to purify and separate these two polymerization values. By-products, ie, low crystalline atactic polymers, are used commercially as components of various adhesive compositions, roofing materials, caulking compounds, and the like.

Recently, new catalysts having higher activity and more stereospecificity than the above-mentioned ordinary catalysts have been developed. The proportion of atactic polymer in polymers made using these catalysts is significantly reduced, and thus the polymerizable product generally requires no purification to remove atactic or low crystalline polymers. do not need. The existing polymer equipment has quickly adapted to the use of these new catalysts, resulting in a severe shortage of low crystalline, atactic polymers.

U.S. Pat. No. 3,789,036 to Longi et al. Discloses a magnesium-supported titanium catalyst, for example, using a co-milled mixture of titanium tetrachloride and magnesium chloride.
A process for making an ethylene-propylene elastomer containing from 20 to about 70% by weight of ethylene is disclosed. This catalyst is not very active and it has therefore been found that the polymers produced in this way contain undesirably large amounts of residual catalyst. Second,
This polymer is more crystalline than desired, as measured by the m / r ratio detailed below. Finally, the low catalyst activity makes the catalyst cost prohibitive.

Accordingly, it is an object of the present invention to provide a novel and highly efficient process for the production of a substantially amorphous polymer of propylene and ethylene.

According to the invention, 85 to 96.5% by weight of propylene and 3.5
Or 15% by weight of ethylene at 54.4 ° C (130 ° F)
At a reactor pressure sufficient to keep the propylene in a liquid phase at a temperature of 9.4 ° C. (175 ° F.), in the presence of 0.7 to 3.0 mol% hydrogen, based on the monomer feed to the process, (A) (i) co-milling a magnesium halide carrier substrate and aluminum trihalide in a molar ratio of 8: 0.5 to 8: 3 without adding an electron donor, (ii) Converting the product of step (i) without addition of an electron donor, in an amount sufficient to provide a molar ratio of magnesium halide to titanium tetrahalide of 8: 0.4 to 8: 1. And (b) 100 mol% of a trialkylaluminum having 1 to 9 carbon atoms in each alkyl group, comprising: 50: 1
Reacting using a composition comprising a sufficient amount of a co-catalyst component to provide an Al / Ti ratio in the range of
Substantially amorphous, random (random) ethylene-propylene having a stereoregularity index m / r in the range of 2.5 to 4 as determined by ^13C NMR spectroscopy and containing up to 15% by weight of ethylene. There is provided a method for producing a substantially amorphous copolymer consisting essentially of ethylene and propylene, comprising recovering a random copolymer.

Preferably, the halide is chloride, the alkyl is an ethyl group, and the alkyl aluminum halide is
Contains two halogen groups. The invention is described below in connection with preferred embodiments of the catalyst system.

Although the present polymerization can be carried out in a batch reactor, it is preferred that a continuous process also be employed to achieve the most random incorporation of the comonomer. Usually, a pressure in the range of about 400 psig to about 550 psig is suitable to keep the propylene in the liquid phase, with the preferred temperature being about 65.6 ° C (150 ° F) to 71.7 ° C (160 ° F).

In order to control the polymer molecular weight and other properties, hydrogen is generally added to the polymerization reactor at a concentration of about 7 to 10 times the amount normally used for the production of isotactic polymers. Furthermore, as the ethylene content of the copolymer increases, it is necessary to increase the hydrogen concentration in the reactor to maintain a constant melt viscosity of the copolymer. For example, about 5% for a 100% increase in ethylene content
A 0-150% increase in hydrogen is required. The hydrogen concentration in the total feed to the reaction zone is preferably from about 1.2 to about
It is in the range of 2.5 mol%.

The solid supported catalyst component is about 8: 0.5-3.0, preferably 8: 1.0
It should have a magnesium chloride to aluminum chloride molar ratio of -1.5.

The molar ratio of magnesium chloride to titanium tetrachloride is about 8: 0.
It is 1-1.0, preferably 8: 0.4-0.6. A critical requirement of the solid supported catalyst component is that electron donor compounds should not be used at any stage of the catalyst preparation. Also,
The polymerization step using the present catalyst should be carried out without adding an electron donor.

Any of the general methods described in U.S. Pat. Nos. 4,347,158 and 4,555,496, which are incorporated by reference in the present application, must be modified to exclude the use of electron donor compounds. It can be used in the preparation of the solid supported catalyst component, except that it does not. Briefly, the improved method involves co-milling magnesium chloride and aluminum trichloride in the absence of an electron donor, and then forming the catalyst support thus formed with titanium tetrachloride, also an electron donor. Co-milling in the absence of body.

The present solid catalyst component consists of about 100 mol% of triethylaluminum as described above. When the amount of ethylene incorporated in the polymer is 15% by weight or less, 10%
It is advantageous to use 0 mol% of trialkylaluminum. The molar ratio of the total organoaluminum promoter to the titanium-containing catalyst component, ie, the Al / Ti ratio, should range from about 50: 1 to about 600: 1, preferably from about 90: 1 to about 300: 1.

The polymerization is carried out in a stirred reactor with an average residence time of about 1 hour to about 3 hours. A sufficient amount of catalyst is provided to the reactor to obtain a polymer content in the reactor slurry of from about 30% to about 60% by weight. The reactor effluent is removed from the reactor and unreacted monomers and hydrogen are removed from the polymer product.

Certain catalysts used in the process of the present invention have the ability to produce polymers with little or no control over the stereochemistry of the propylene units, and have the ability to produce ethylene as irregularly as possible. It also has the ability to be incorporated into randam) to give the polymer chain maximum disorder.

Because of the high activity of this catalyst, the process is highly efficient, typically yielding a polymer output of at least 7000 pounds polymer / lb Ti catalyst / hour.

The products of the process according to the invention have a stereoregularity index m / r of about 2.5 to 4. This value is based on ¹³ C nuclear magnetic resonance (NM
Measure directly by the R) method. “M” and “r” describe the stereochemistry of adjacent pairs of propylene groups to which one or more ethylene groups are attached, “m” represents a meso form, and “r” represents a racemate. An m / r ratio of 1.0 represents a syndiotactic polymer, and an m / r ratio of 2.0 represents a truly atactic material. Isotactic materials will theoretically have a ratio close to infinity, and many by-product atactic polymers with sufficient isotactic content will have a ratio of 50 or more become. In the case of the propylene homopolymer produced under the same conditions as the random polymer except that the feedstock does not contain ethylene, the same group, that is, the number average continuous length n of the meso group and the racemic group, and The m / r ratio has been found to be substantially consistent. Therefore, it has been determined that the stereoregularity is independent of the comonomer content in the polymer. Also, in the most random manner, the comonomer, eg, ethylene, is distributed throughout the polymer molecule. Methods used to calculate n for homopolymers are described in JCRandall, Polymer Science Magazine (J.POLYM.SCI.),
Polymer Physics (POLYM. PHYS. ED.), 14 , 2083 (1976). The stereoregularity index m / r is
g), macromolecules (MACROMOLECULES), 17 , 1950 (1984), obtained by taking the reciprocal of the r '/ m' ratio calculated according to the method proposed by:

The novel polymer has a very low heat of fusion as measured by differential scanning calorimetry (DSC) technology. This allows
It is shown that the polymer is amorphous and that there is no significant crystallinity in the polymer structure.

The polymer contains only very low concentrations of residual catalyst. For example, the total ash content is generally less than about 500 ppm, and the titanium content does not exceed about 2 ppm and generally is less than about 1 ppm.

Various additives such as an antioxidant,
UV stabilizers, pigments and the like can be incorporated.

The polymer products of the process according to the invention are useful in various fields of application, for example in adhesives, caulking and sealing compounds, roofing compositions, cable and wire flooding compounds and the like. Such excellent characteristics. By varying the comonomer content in the polymer and the amount of hydrogenation to the reactor, the properties can be tailored for any desired application. Important product properties include melt viscosity, ring and ball softening points (ring a
nd ball softning point, needle pen
etration) and open time.

Melt viscosity at 375 ° F. was determined using a Brookfield RVT viscometer and a # 27 spindle using ASTM test method D-3236.
Measured by Hydrogen is used to control the molecular weight and also the melt viscosity. It has been found that as the ethylene content increases, more hydrogen is required to maintain a constant viscosity level. Preferred viscosities for use as wire flooding compounds are from about 100 to about 500 cps. Hot melt
The preferred viscosity range for the adhesive is about 1000 to 5000 cps at 375 ° F. For other applications, for example for bitumen modified products, the polymer component should have a viscosity of 5000 cps or more, preferably in the range of about 10,000 to about 25,000 cps.

Ring and ball softening points are measured using the ASTME-28 test method. The variables affecting the softening point are the ethylene content of the polymer and the concentration of triethylaluminum in the organoaluminum promoter used in the polymerization step.
Decreases in ethylene content and diethylaluminum chloride concentration in the cocatalyst both cause an increase in ring and ball softening points. The preferred range for this property is about 113 ° C
(235 ° F) to about 149 ° C (300 ° F).

Needle penetration is another test that measures the flexibility of a material, in which case the resistance to penetration is measured according to ASTM test method D-1321. The penetration values of the copolymers according to the invention typically range from 10 to about 75 dmm (1 dmm = 0.1 mm). Process variables similar to those for the ring and ball softening points affect this property.

One of the most important test methods for hot melt adhesives is probably open time. This test is an indication of the elapsed time between applying the adhesive to the kraft paper and bonding the kraft paper laminate. This is a very important property for the user, since the user must know how long after the application of the adhesive the second paper should be added. In this test, 81/2 "x 1
Pull down on 1 ”kraft paper sheet with back side up (d
rawdown) Adhere to the plate. The polymer sample was placed along a Bird drawdown applicator for 191 minutes.
Heat to 375 ° F (° C). At this temperature the applicator is placed on kraft paper and a drop of molten polymer is placed near the edge. The polymer is stretched into a smooth film and the stopwatch is started when it reaches the bottom of the paper. Ten
At intervals of seconds, a previously cut strip of kraft paper is placed across the above film (back side down, transverse to machine direction) and pressed with rubber rollers. After the last strip has been applied and subsequently left for 5 minutes, the strip is removed with a smooth and quick action. 90% open time
Or, it is defined as the longest time when more fibers remain. This open type should preferably be in the range of 10 to 60 seconds.

Another advantage of the polymer according to the invention is that the productivity ratio of the particular catalyst used in the present polymerization is very high,
It contains only an extremely small amount of residual catalyst. It is not necessary to remove this small amount of catalyst from the polymer.

 The following examples illustrate the invention.

Example 1-6 (Reference Example) A polymer was produced by a large-scale continuous pilot lamp operation.
Was. Here, monomer, hydrogen and catalyst components are added to the stirred reactor.
Was applied individually and to continuous drops. The total monomer feed rate is
This corresponded to a residence time in the reactor of about 2 hours.
The catalyst organoaluminum compound is triethylaluminum.
Of aluminum (TEA) and diethylaluminum chloride (DEAC)
Heptane solution of equimolar mixture. Solid supported tetrachloride
The titanium catalyst component has a titanium content of about 2.5% by weight
And preferred as disclosed in U.S. Pat.No. 4,347,158
With technology improvements, i.e. all process steps
To be carried out without the presence of child donor compounds
Manufactured in a modified only way. The above solid catalyst component
10% by weight mixed in a 50/50 mixed solvent of petroleum and mineral oil
The mixture was pumped into the reactor. The above two catalyst components
Is a rate directly proportional to the rate of polymer formation, and
The polymer solids concentration in the slurry is typically from about 40% to about 60%.
% Was added in an amount sufficient to maintain a value in the% range. catalyst
What is the productivity (pound polymer / pound Ti catalyst component)
Also in the case of
Calculated from body content and titanium catalyst addition rate
Was. The polymer product is separated from unreacted monomers and
Box (Isonox ) Stabilized using 129 and then tested
To

Table 1 summarizes the relevant operating conditions and physical test results. All product properties of Examples 1-6 (Reference Example) are the result of operating within the claimed limits of the invention.

Comparative Example 7 In this comparative example, US Pat.
The conditions of Example 6 of 036 were modified slightly to obtain a product containing less than 30% by weight of ethylene and having measurable properties of melt viscosity, softening point, and needle penetration. Volume containing 1683 stainless steel balls weighing 1683 g
A catalyst was prepared by adding 29.7 g of anhydrous magnesium chloride and 1.25 g of titanium tetrachloride to a 0.6 liter steel mill. This mixture was milled under a nitrogen atmosphere at 20 ° C. for 64 hours. 1 liter reactor was purged with N _2, was added 25% heptane solution 2.7ml and 1% catalyst solution in mineral oil 1.76ml of triisobutylaluminum (0.0157g). Hydrogen was added to bring the reactor pressure to 100 psig (the reactor pressure at which hydrogenation was 1 psig). 160 g of propylene were added and the temperature was raised to 60 ° C. (reactor pressure = 490 psig). Then
Ethylene was added to bring the total reactor pressure to 515 psig and ethylene was maintained at this level for 4 hours. Since 58 g of a polymer were obtained, the catalytic activity was 925 g / g catalyst / hour. For ease of comparison, the properties of the resulting polymer were measured in Example 6
Are shown in Table 3.

As can be seen from the above data, the two polymer products are quite equivalent in ethylene content, melt viscosity, and softening point, but using the Longi et al. Catalyst of Comparative Example 7, Polymers having m / r ratios exceeding the limit value 4.0 of the present invention are produced. Also, the catalytic activity of Longi et al. Catalyst is much lower than that of Example 6, ie, 92%.
Because of 5 to 15,130 pounds polymer / pound catalyst / hr, the ash and residual catalyst content of the polymer of Comparative Example 7 is significantly higher than that of the polymer of Example 6, for example, the total ash content is 1766 230 ppm.

Example 8-10 These three examples are the same as Example 1 except for the following.
-6 was performed using substantially the same operating conditions.

The organoaluminum compound is fed to the reactor in the form of a stream of pure triethylaluminum, and the solid catalyst component containing about 2.5% by weight of titanium is converted to 6% by weight in pure petroleum.
It was pumped into the reactor in the form of a mixture. The residence time was 1.8 hours and the solids concentration in the reactor was maintained at 40% by weight.
Table 4 shows the numerical operating conditions and the properties of the polymer product.

Example 11 (Reference Example) and Comparative Example 12-13 These Examples (Reference Example) and Comparative Examples each have a polymer having an ethylene content of more than 15% by weight and an m / r ratio in a required range. It is necessary to use a mixture of a trialkylaluminum and a dialkylaluminum halide co-catalyst in the production of a compound having an acceptable yield.

The experiments were performed in a 1 liter jacketed autoclave equipped with a magnetically connected stirrer. The temperature of the autoclave was controlled using an equal mixture of glycerol and water as the heat exchange fluid flowing through the jacket. The temperature of this fluid was controlled by a microprocessor, the temperature indicator of which was an iron / constantan thermocouple in an autoclave. Using this system, the set point temperature could be kept at ± 0.2 ° C.
All monomers are of polymerization grade purity 99%,
Prior to use, it was passed through a molecular sieve bed and the same catalyst bed to remove oxygen. 99% hydrogen
Was used as it was. The aluminum alkyl solution was purchased at 25 W / W% in normal heptane and used as it was. A 1% catalyst slurry was made in degassed mineral oil using the same type of catalyst as in Examples 1-8. The autoclave was heated to 90 ° C. for 30 minutes with a slow nitrogen purge prior to each use. After cooling to 30 ° C., the nitrogen atmosphere was replaced by a propylene purge. Alkyl solution and catalyst slurry are separated vial (septumvial) in dry box (nitrogen atmosphere)
It was prepared in-situ and purged with nitrogen for removal and slightly pressurized to avoid contamination. The alkyl solution and catalyst slurry were introduced into the reactor using a hypodermic syringe which had been previously washed with deionized water, dried at 120 ° C., and purged with nitrogen prior to use. In Example 11 (Reference Example), TEA
0.34 ml, 0.34 ml of DEAC (Al-1.77 × 10 ^-3 mol / l), and 1
W / W% catalyst slurry (titanium content 2.5W / W%) 0.58
% Was added to the autoclave. Add hydrogen and increase the partial pressure
70 psg. 0.6 liter of propylene was introduced using a sight gauge and nitrogen pressure. The reactor contents were heated to 60 ° C. and maintained at this temperature with stirring at 500 rpm. When the temperature stabilizes at 60 ° C (5-10
Min) Add ethylene to the reactor and add 50ps to the reactor pressure
ig was kept at a high constant overpressure. One hour later,
The temperature was reduced and excess propylene was vented. The resulting ethylene-propylene copolymer was dried under vacuum at 40 ° C. overnight.

In Comparative Example 12, 0.68 ml of TEA was used exclusively,
On the other hand, in Comparative Example 13, only the same amount of DEAC was used.
Table 5 lists the relevant data of these comparative examples.

As can be seen from the data above, a mixture of TEA and DEAC is used (as in Example 11) instead of 100% TEA.
The result is that a polymer product with an unacceptable m / r ratio is obtained. The use of 100% DEAC as a cocatalyst results in no polymer formation.

It is to be understood that many modifications and improvements can be made to the method of the present invention. All such developments are considered to be within the scope of the invention as defined by this specification and the appended claims.

The main features and aspects of the present invention are as follows.

1. 85 to 96.5% by weight propylene and 3.5 to 15% by weight ethylene at 54.4 ° C (130 ° F) to 79.4 ° C (175 ° C).
At a reactor pressure sufficient to keep the propylene in the liquid phase at a temperature of (F) and in the presence of 0.7 to 3.0 mole percent hydrogen, based on the monomer feed to the process, i) co-milling the magnesium halide support substrate and aluminum trihalide in a molar ratio of 8: 0.5 to 8: 3 without adding an electron donor, (ii) then step (i) Is co-ground with a sufficient amount of titanium tetrahalide to provide a molar ratio of magnesium halide to titanium tetrahalide of 8: 0.4 to 8: 1 without adding an electron donor. A solid catalyst component prepared by a process comprising: (b) 100 mol% of a trialkylaluminum having 1 to 9 carbon atoms in each alkyl group, 50: 1
Reacting using a composition comprising a sufficient amount of a co-catalyst component to provide an Al / Ti ratio in the range of
Substantially amorphous, random (random) ethylene-propylene having a stereoregularity index m / r in the range of 2.5 to 4 as determined by ^13C NMR spectroscopy and containing up to 15% by weight of ethylene. A method for producing a substantially amorphous copolymer consisting essentially of ethylene and propylene, comprising recovering a random copolymer.

2. The method according to claim 1, wherein each halide is a chloride and each alkyl is an ethyl group.

3. The method of claim 1 wherein said pressure is from about 400 psig to about 550 pisg and said temperature is from about 65.6 ° C (150 ° F) to 71.7 ° C (160 ° F).

4. The method of claim 1, wherein said magnesium halide to aluminum trihalide ratio ranges from about 8: 1 to about 8: 1.5.

5. The method of claim 1, wherein said magnesium halide to titanium tetrahalide ratio ranges from about 8: 0.4 to about 8: 0.6.

6. The method of claim 1, wherein said Al / Ti ratio is maintained between about 90: 1 and about 300: 1.

7. The process of claim 1 wherein said hydrogen is maintained at about 1.2 to about 2.5 mole percent based on the total monomer feed to the process.

8. The process of claim 1 wherein the process is carried out under continuous conditions with an average residence time of about 1 to about 3 hours.

9. The method of claim 1 wherein the solids content of the reactor slurry is maintained between about 30% and about 60% by weight.

10. The process of claim 1 wherein said catalyst composition has an activity of at least 7000 pounds polymer / pound Ti catalyst / hour.

11. The recovered copolymer is approximately 100 at 191 ° C (375 ° F).
2. The method of claim 1 having a melt viscosity of from about 25,000 cps to about 25,000 cps.

12. The recovered copolymer is from about 113 ° C (235 ° F) to about 149 ° C.
The method of claim 1 having a ring and ball softening point of 300 ° C (300 ° F).

13. The method of claim 1, wherein the recovered copolymer has a needle penetration of about 10 to about 75 dmm.

14. The first copolymer as described above, wherein the recovered copolymer has an open type of about 10 to about 60 seconds.
The method described in the section.

15. The method of claim 10 wherein the recovered copolymer has a total ash content of about 500 ppm or less.

16. The method according to claim 10, wherein the recovered copolymer has a titanium content not exceeding about 2 ppm.

 ────────────────────────────────────────────────── ─── Continued on the front page (56) References Patent 2505469 (JP, B2)

Claims (1)

(57) [Claims] 1. A method according to claim 1, wherein 85 to 96.5% by weight of propylene and 3.5 to 15% by weight of ethylene are reacted at 130 ° F. to 54.4 ° C.
At a reactor pressure sufficient to keep propylene in a liquid phase at a temperature of 4 ° C (175 ° F), based on the monomer feed to the process
(A) (i) adding a magnesium halide support substrate and aluminum trihalide in a molar ratio of 8: 0.5 to 8: 3 in the presence of 0.7 to 3.0 mol% of hydrogen, and adding an electron donor. (Ii) The product of step (i) is then milled without addition of an electron donor, with a molar ratio of magnesium halide to titanium tetrahalide of 8: 0.4 to 8: 1. A solid catalyst component prepared by a process comprising co-grinding with a sufficient amount of titanium tetrahalide to provide: (b) from 100 mole percent of a trialkylaluminum having 1 to 9 carbon atoms in each alkyl group. Yes, 50: 1
Reacting using a composition comprising a sufficient amount of a co-catalyst component to provide an Al / Ti ratio in the range of
Substantially amorphous, random (random) ethylene-propylene having a stereoregularity index m / r in the range of 2.5 to 4 as determined by ^13C NMR spectroscopy and containing up to 15% by weight of ethylene. A method for producing a substantially amorphous copolymer consisting essentially of ethylene and propylene, comprising recovering a random copolymer.